The National Cancer Institute (NCI, the largest of the institutes of the National Institutes of Health, NIH) recently published an excellent fact sheet describing many aspects related to prostate-specific antigen (PSA) testing. Specific subjects addressed include: a) what is the PSA test? b) Is the PSA test recommended for prostate cancer screening? c) What is a normal PSA result? d) What if screening shows an elevated level? e) Limitations and potential harms of using the PSA test for prostate cancer screening; f) Recent research on prostate cancer screening; g) How is the PSA test used in men who have been treated for prostate cancer? h) What does a PSA increase mean for men who have been treated? i) How are researchers trying to improve the PSA test?